The technology of the present disclosure relates to an image forming apparatus.
In an electrophotographic image forming apparatus, a surface of a photosensitive drum is uniformly charged to a predetermined polarity, light corresponding to predetermined image data is irradiated to the charged surface of the photosensitive drum so as to form an electrostatic latent image, the electrostatic latent image is developed to form a toner image, and the toner image is transferred to a member to be transferred (a paper, an intermediate transfer belt and the like) by a transfer roller. The aforementioned transfer roller is connected to a high voltage power supply. Furthermore, by a transfer electric field formed between the transfer roller and the surface of the photosensitive drum, the toner image of the surface of the photosensitive drum is transferred to the member to be transferred.
As the charging method of the aforementioned photosensitive drum, there is proposed a contact charging method for allowing a charging member to abut the photosensitive drum and charging the surface of the photosensitive drum to a predetermined polarity. According to the contact charging method, it is advantageous that it is possible to suppress an ozone generation amount as compared with a conventional non-contact type corona charging method (a so called scorotron method).
In a charging device employing such a contact charging method, a charging roller method using a conductive roller in the charging member is proposed. According to this method, it is possible to uniformly charge the surface of the photosensitive drum.